REASON 70:Years of progress will be undone if Mitt Romney appoints our next Supreme Court justices.

Enthusiasm in American politics is a rare commodity, an emotion mostly reserved for the very partisan or the very uninformed. I’ve felt it once or twice, in passing. I don’t miss it. This year, I will vote for Obama. It will be a heartfelt, serious, and considered vote. If not exactly enthusiastic, it is at least committed.

Because this is true: Obama has a lot to take credit for. Under his watch, an economic catastrophe was averted, and millions of Americans who would otherwise be unemployed are working as a result. Obama has worked within the constraints of a broken political system, against a delusional opposition, and has made the usual sorts of compromises required of American presidents. Failures, you might call them. He has not closed Guantánamo. He has deported hundreds of thousands of immigrants, breaking up countless families. He has pursued a militaristic policy of drone strikes on sovereign nations. He has all but abandoned the issue of climate change. I'm not blind to the impact of these policies. It’s not the clean record I would have liked him to have at this point. It’s the record of a centrist American president, less than ideal, but far better than most.

Campaigning on hope in the midst of an economic collapse is a lot more inspiring than trying to navigate out of that same crisis. I wrote in 2008 that Obama’s long-term impact would be as much cultural as political, and looking back on that statement, I see that it was a way to inure myself against the inevitable disappointment that would come. But the statement remains essentially true: The mere existence of an American president like Obama broadens the conversation, announces a cultural and demographic shift that has been a long time coming, and is mostly irreversible.

The one institution where some of that progress can be undone is the US Supreme Court. This is where the next generation of battles will be waged, either to ratify changes already underway, or roll them back. There are two numbers you should keep in mind when you go vote in November: 79 and 74. Those are the ages of Justices Ruth Bader Ginsberg and Stephen Breyer, respectively. Ginsberg and Breyer are lucid, by all accounts in good health, and could live for another ten years or longer. But they might also retire. And I shudder to think what would become of an already right-leaning court if even one of these two liberal justices were to be replaced under a Romney presidency. For starters: a further dismantling of affirmative action, an erosion of reproductive rights, more restrictive and punitive immigration laws, legal justifications for torture, an increase in executive power, and legalized discrimination against gays and lesbians.

If that is not your agenda, then you should go to the polls. Set aside everything else, and vote for Obama.